node: inspector/debugger v26 compat fixes (+17 tests)

[cirospaciari]

What

Second-wave node:inspector / node inspect compat fixes on top of the inspector/CDP-on-CLI stack (#31823 → #34719 → #35396), vendoring 17 more upstream Node v26.3.0 test-inspector-* / test-debugger-* tests that now pass.

Verified by running every test-inspector-* / test-debugger-* file in the tree (133 files: the 116 the base already carries plus these 17) CI-style against the debug build: 94 pass, and every failure is in the drop list below with its blocking cause. Preflight (byte-verbatim check, per-file pass, throw-canary) is clean.

Fixes

Each item names the defect; the tests it unlocks are in parentheses. Everything else in the diff is vendored test files.

CDP adapter (src/js/internal/inspector/cdp.ts)

• The pause that ends an --inspect-brk/--inspect-wait park is now reported with V8's reason Break on start; NODE_INSPECT_RESUME_ON_START and the debugger REPL header branch on it (test-debugger-auto-resume).
• Preview shape: entries omitted from empty Map/Set previews; entries of a Map/Set nested inside another preview elided to overflow; JSC-only line/column/sourceURL/originalLine/originalColumn own properties dropped from error previews with stack listed first; and stack recovered via Runtime.getProperties when JSC's five-property preview cap crowds it out (test-debugger-probe-json-preview).
• Thrown evaluations: exceptionDetails now carries text: "Uncaught", a description embedding the formatted stack, a structured stackTrace, scriptId, and the throwing statement's source-mapped position (test-debugger-probe-expression-throws).
• Pre-parse breakpoints are re-set through the script's source map in two phases — all removals, then all re-adds. JSC resolves distinct requests on an unmapped line forward to one shared pause location, and removing one of them after a re-added breakpoint had resolved there cleared that one too (test-debugger-probe-explicit-column).
• A stale pass-through pre-parse breakpoint can fire before the backend processes the removal issued during retranslation (scripts start executing at parse). A pause it causes off the re-set line has no V8 equivalent and is resumed silently; on the re-set line it is the requested breakpoint and is reported under the id the client knows (test-debugger-sb-before-load, without regressing test-debugger-probe-late-resolution / -multi-location).
• Debugger.setBreakpoint / setBreakpointByUrl replies translate their resolved locations back to original coordinates; the REPL's breakpoints list printed generated line numbers.
• console.profile() / console.profileEnd() (JSC's programmatic ScriptProfiler tracking) are announced as Profiler.consoleProfileStarted / consoleProfileFinished (test-debugger-profile).
• HeapProfiler.takeHeapSnapshot implemented for remote sessions by building the V8-format snapshot on the inspected thread (Bun.generateHeapSnapshot("v8")) and streaming addHeapSnapshotChunk events (test-debugger-heap-profiler).

Native

• process.debugPort reflects the actually-bound CLI inspector port (was always 9229), reported from the debugger thread when the node-CDP endpoint comes up (test-inspector-port-zero).
• --inspect startup blocks until the debugger thread finishes server startup, so the Debugger listening on ws://… banner is ordered before any script output — Node binds its inspector synchronously and this test scrapes stderr for that line before reading stdout. Implemented with the existing startup futex: armed in Debugger::create before the spawn, cleared on every debugger-thread exit path (test-inspector-port-zero; a -p/short script could previously exit before the banner).
• --inspect-port=[host:]port is parsed: it names the port for an active --inspect listener and is reflected by process.debugPort even without one — --inspect-port=0 alone reports 0 and starts no server. An explicit --inspect=<port> keeps its own port (test-inspector-port-zero).

bun inspect probe mode

• Bun's inspector banner is stripped from probe-report stderr fields; Node targets print nothing beyond the listening lines the filter already drops (test-debugger-probe-failure-process-exit).

Test harness

• test/common/inspector-helper.js synced verbatim to v26.3.0 — the base carried a pre-waitUntil copy (test-inspector-network-data-received / data-sent).

Vendored tests (17, byte-verbatim)

See the test commit for the list; fixtures fixtures/debugger/probe-exits-during-probe.js, probe-multi-statement.js, probe-throwing-getter.js come along.

Evaluated and not vendored — blocking cause per file

• Worker inspector (inspector.open() in workers is the base stack's deliberate ERR_WORKER_UNSUPPORTED_OPERATION stub; NodeWorker attach/sendMessageToWorker need it): test-inspector-close-worker, -exit-worker-in-wait-for-connection, -exit-worker-in-wait-for-connection2, -connect-main-thread, -async-hook-after-done.
• internalBinding shims missing (async_wrap, inspector) and the SIGUSR1/_debugProcess stub decision (the base PR reverted _debugProcess to a stub because Bun has no SIGUSR1 inspector handler): test-inspector-async-call-stack, -async-call-stack-abort, -async-hook-setup-at-signal, test-debugger-pid.
• Bun runs CommonJS in strict mode, so the REPL's exec a={}; a throws where Node's sloppy wrapper creates a global: test-debugger-object-type-remote-object (its Map/Set preview assertions now pass; this is the remaining blocker).
• Bun's uncaught-error stderr format differs from Node's (error: style, no Node.js vX trailer): test-debugger-probe-script-throws, -probe-target-syntax-error.
• bun accepts unknown CLI flags where node exits 9 with bad option: test-debugger-probe-launch.
• Upstream cwd assumption (Node's runner cwd == repo root == the test's ../..; Bun's CI cwd is the bun repo root, which nests these tests deeper): test-debugger-profile-command, test-inspector-overwrite-config.
• JSC stepping anchor from the --inspect-wait initial pause: the first n steps to the last top-level statement instead of the next line (the CLI parks with --inspect-wait + Debugger.pause, and stepping from that pause is mis-anchored in JSC): test-debugger-set-context-line-number, -run-after-quit-restart.
• Nondeterministic under Bun (three consecutive runs failed at three different assertions — breakpoint resolution races the 10ms timers in the fixture): test-debugger-break.
• JSC TDZ ReferenceError text differs from V8 (Cannot access 'x' before initialization vs x is not defined at break-on-start): test-debugger-watchers.
• vm contexts are not inspector execution contexts: test-inspector-contexts.
• In-process Runtime.awaitPromise never settles (pre-existing in the base stack — the in-process backend channel has no async reply path): test-inspector-promises.
• In-process pause broadcast / scope enumeration gaps: test-inspector-multisession-js, -bindings, -async-context-brk, -debug-async-hook.
• --experimental-webstorage / Storage domain: test-inspector-dom-storage.
• internal/deps/undici real internal module: test-inspector-network-fetch.
• Runtime.evaluate timeout param (JSC has no evaluate watchdog): test-inspector-runtime-evaluate-with-timeout.
• cluster inspect-port allocation not implemented (cluster.settings.inspectPort execArgv rewriting): test-inspector-port-zero-cluster, sequential/test-inspector-port-cluster.
• scripts must list node:internal/* scripts Bun does not have: test-debugger-scripts.
• fetch/node:http network-inspection instrumentation not implemented (only the manual Network.* emit API exists): test-inspector-network-content-type, -network-http, -network-http2, -network-websocket, sequential/test-inspector-network-resource.
• --inspect-brk-node + node:internal/bootstrap/realm script: test-inspector-inspect-brk-node.
• bun inspect probe failure-path fidelity (JSC's "Can only perform operation while paused." vs V8's "Must be paused or waiting to pause"; disconnect-vs-timeout classification when a probe closes the inspector): test-debugger-probe-failure-resume, -probe-failure-hang-during-evaluate.

[github-actions]

Found 4 issues this PR may fix:

1. Debugger not work with console.profile #22095 - PR implements proper CDP Profiler.consoleProfileStarted/consoleProfileFinished events for console.profile()/console.profileEnd(), directly addressing debugger breakpoints not working between profile calls
2. Breakpoints are being hit at unexpected locations when using Bun for debugging #15131 - PR fixes breakpoint location translation by mapping Debugger.setBreakpoint/setBreakpointByUrl resolved locations back through source maps to original coordinates, addressing breakpoints hitting at unexpected locations
3. Debugger ignores breakpoint on first line #8282 - PR adds two-phase pre-parse breakpoint retranslation with #supersededBreakpoints tracking, which fixes breakpoints set on the first line being ignored
4. bun processeses appear in VS Code Attach to Node Process but don't work #28883 - PR fixes process.debugPort to reflect the actually-bound inspector port instead of hardcoded 9229, addressing the wrong port shown in VS Code's "Attach to Node Process"

If this is helpful, copy the block below into the PR description to auto-close these issues on merge.

Fixes #22095
Fixes #15131
Fixes #8282
Fixes #28883

🤖 Generated with Claude Code

[robobun]

^{Updated 5:28 PM PT - Jul 24th, 2026}

@cirospaciari, your commit f9bddd5 is building: #79880

[robobun]

^{Updated 5:30 PM PT - Jul 24th, 2026}

@autofix-ci[bot], your commit 7aa5bb8 is building: #79883

[cirospaciari]

🤖 Coalesced into #35396 (its direct parent in the inspector lineage, per review-load consolidation) — merged clean, 77-test preflight green. Closing.